Which instruments use static pressure only?

Which instruments use static pressure only?

• A. VSI and Airspeed
• B. Airspeed only
• C. Altimeter and Airspeed
• D. Altimeter and VSI

Answer: (D)

Static pressure is the ambient air pressure at the aircraft’s location, measured by the static port. The altimeter is basically an aneroid barometer that responds to this static pressure to display altitude. The vertical speed indicator uses changes in static pressure over time to show how quickly you’re climbing or descending. It does not rely on dynamic pressure from forward airspeed. The airspeed indicator, on the other hand, relies on dynamic pressure, which is the difference between ram (pitot) pressure and static pressure, to show speed. So the instruments that use static pressure only are the altimeter and the VSI.

Static pressure is the ambient air pressure at the aircraft’s location, measured by the static port. The altimeter is basically an aneroid barometer that responds to this static pressure to display altitude. The vertical speed indicator uses changes in static pressure over time to show how quickly you’re climbing or descending. It does not rely on dynamic pressure from forward airspeed. The airspeed indicator, on the other hand, relies on dynamic pressure, which is the difference between ram (pitot) pressure and static pressure, to show speed. So the instruments that use static pressure only are the altimeter and the VSI.